light pollution filters

programmer · #1 28-03-2008, 08:50 AM

Hi all

What are people's opinions on filters to reduce light pollution? I've read their benefit is minimal these days with modern light pollution in the cities and suburbs.

Are they worth the spend at all, or are the benefits just too small to be worthwhile? Which provide any benefit (for visual).

I live in suburban Melbourne.

Thanks.

Edit: BTW I have searched for and read some threads on this, but they are either astrophotography-oriented or comparisons of a couple of specific models, etc. To me it seems like the answer is "don't bother", but any marginal improvement with a small outlay would be nice, mainly for DSO's. I know nothing beats dark skies but I can't wait until my retirement

leon · #2 28-03-2008, 12:18 PM

Absolutely do bother, some of the better light reduction filters are worth every cent, although not cheap.

Hutech in the States can provide some excellent filters for your needs, I use then constantly, and it will increase your exposure times many times over if you choose the correct filter.

If you are in a light polluted area, and want to image, they are necessary, although nothing will beat the dark skies of which you speak.

Leon

coldspace · #3 28-03-2008, 02:42 PM

I live in the outer suburbs of Brisbane and have started using an Astronomic CLS filter for visual. It has made a bit of difference by darkening the back ground sky so the object stands out better. Diffinately improves the contrast but is still no substitute for dark skies. Nothing is but still makes an improvement. This filter is recommended for aperatures 10 inch and up as it will also cut back abit of the "good light". There is another version for smaller aperatures. Orion put out their versions as well and are about half the price and from what I hear work OK as well. Don't expect over the moon results with these types of filters but they are better than nothing for visual. Everything that helps if worthwhile IMHO.

Matt

programmer · #4 28-03-2008, 02:56 PM

Thanks for the input, I check out those recommendations. It's purely for visual at this stage.

wavelandscott (Scott) · #5 28-03-2008, 03:33 PM

Quote:

Originally Posted by coldspace

I live in the outer suburbs of Brisbane and have started using an Astronomic CLS filter for visual. It has made a bit of difference by darkening the back ground sky so the object stands out better. Diffinately improves the contrast but is still no substitute for dark skies. Nothing is but still makes an improvement. This filter is recommended for aperatures 10 inch and up as it will also cut back abit of the "good light". There is another version for smaller aperatures. Orion put out their versions as well and are about half the price and from what I hear work OK as well. Don't expect over the moon results with these types of filters but they are better than nothing for visual. Everything that helps if worthwhile IMHO.

Matt

This matches my experience as well with this filter...

The other thing to keep in mind is that in a light pollution situation, sometimes it is difficult for your eyes to ever get dark adapted...this is also a hinderance to pulling out those faint fuzzies from town...

The DGM Optics narrow passband filter is also one to consider...

Karlsson · #6 28-03-2008, 05:00 PM

A while ago I compared Astronomik CLS with their UHC-E and an Orion UltraBlock, in a filter wheel in an 8" f/6 Newt in suburban Sydney... Performance depends very much on the object of course, so I don't think there was a clear winner.

But if I were to have only one out of those 3 (under less than black skies) it would be the UHC-E - just a bit more punch than the CLS, and not as aggressive as the UltraBlock... closest to 'jack-of-all-trades' in this environment, if there is such a thing.

I have never looked through the DGM-NPB though, but I have never heard any negative feedback about it...

just my $0.02

programmer · #7 28-03-2008, 05:35 PM

Interesting.. Might have to just toss a coin in the end. It does discourage me a little when some people say they never use theirs. I guess it's personal taste in the end. I suppose if I get the 'wrong' one I can always flog it off for minimal loss

Jen · #8 31-03-2008, 05:34 PM

Hi Programmer

move to the country

the sky is awsome here

Meadehead · #9 31-03-2008, 11:42 PM

Hi Programmer,

I recently started using an Astronomic UHC filter for use mainly with emission nebulae eg orion & carina and it does improve contrast.

programmer · #10 01-04-2008, 12:05 AM

Quote:

Originally Posted by Jen

Hi Programmer

move to the country

the sky is awsome here

I wish! Never really thought I'd say that, and it probably won't happen in the next 20 years.. but one day I will. By they who knows how far the Melbourne skyglow will reach

programmer · #11 01-04-2008, 12:08 AM

Quote:

Originally Posted by Meadehead

Hi Programmer,

I recently started using an Astronomic UHC filter for use mainly with emission nebulae eg orion & carina and it does improve contrast.

Sounds like a popular one.. I'll be saving up

Screwdriverone (Chris) · #12 01-04-2008, 01:07 AM

Hi Programmer,

I bought a Baader UHC-S High Transmission Nebulae filter and was astounded at the difference I could see in Nebulae (M42 and Eta Carina for example) from my suburban skies. M42 in Orion was about 3 times bigger with this filter in. It brought out the contrast and made the whole thing more visible. However, thats all it did. The light loss overall for this one was very noticeable on everything else and I couldnt really see anything while roaming around. Basically it was a nebula filter ONLY and it did that job VERY well ($129). This is my original post on the UHC after Les pointed out this UHC-S filter's limitations to me http://www.iceinspace.com.au/forum/s...ad.php?t=29679

I swapped it over the next day for a Baader Moon and Skyglow Filter ($85) and used the difference to buy a weather station and another eyepiece and I must say the decision was worth it.

Planetary detail is up, more objects visible in polluted moonlit nights and generally more stars visible. I hardly take this out of the 12.5mm ED eyepiece I have as it helps dramatically in my area as the point I look at the most is South East and this just happens to be in the direction of Sydney and the Blacktown area.

I have heard that the OIII filter is the weapon of choice for the people who say they only need or want one filter and that's the one. However, it would probably be specific to DSO's and blot out most general sky targets like the UHC-S did? I think for general viewing overall, the M&S one is hard to beat for price and performance, especially in light polluted skies!

Chris

koputai (Jason) · #13 01-04-2008, 09:07 AM

I have the Orion Ultrablock and gave it a good workout last night. The difference it makes on nebulae is dramatic. The Carina nebula just goes on and on, with whisps and lanes all over the place, and about three times as big as without the filter. It does give everything a green tinge, and is useless on everything else, but it does an amazing job on nebulae.

Cheers,
Jason.

programmer · #14 01-04-2008, 10:49 AM

Quote:

Originally Posted by Screwdriverone

I think for general viewing overall, the M&S one is hard to beat for price and performance, especially in light polluted skies!

Chris

Thanks for the detailed response. The Baader M&S sounds like great value. Perhaps getting a more general purpose one like that initially, and a more nebula specific one down the track. Do all stores have such a good return policy as you've described? I go to Bintel in Melbourne.

Quote:

Originally Posted by koputai

I have the Orion Ultrablock and gave it a good workout last night. The difference it makes on nebulae is dramatic.

hmm i'm drooling. I love DSO's and anything that would make them jump out a bit would be great, even if it means some filter swapping as I roam around the sky. Thanks for the info.

programmer · #15 01-04-2008, 11:16 AM

Just had a look at the Bintel site. Any opinions on the Bintel OIII ($69), nebula contrast ($79) and skylight ($49) filters? Better to spend a bit more?

JohnH · #16 01-04-2008, 01:20 PM

Programmer,

You may have got mixed messages about these filters becasue there are basically two different choices here, L(ight) P(ollution) R(ejection) and U(ltra) H(ight) C(ontrast).

The former attempts to block all the wavelengths common to streetlighting - eg Sodium and Mercury lights etc the latter seeks to permitt only the specific wavelengths from emission nebulae to pass.

The LPR is generally cheaper and works in many situations the UHC is more expensive and works only on nebulae but there it works better.

Both will introduce color casts (green/purple)

OIII is a more restrictive filter still and is king if you seek Planetay Nebs.

Hope that helps!

JimmyH155 · #17 01-04-2008, 01:27 PM

I have an OIII filter, and every time I have tried it, I end up seeing nothing at all (or maybe a dim red speck) so dont use it now.Waste of time.
I tried out my Baader nebula filter on M42 last night, and whilst it did make the dark bits a bit darker, it darkened the stars as well, so I took it off and saw the nebulosity just as well - also 6 stars in the Trapesium

I am in Northern suburbs Brissie, and last night was the clearest night since before Christmas.... so what did the neighbours do??? Yes, switched their outdoor lights on and then went indoors. AAAAAGGGGHHHHH

programmer · #18 01-04-2008, 01:29 PM

Quote:

Originally Posted by JohnH

Programmer,

You may have got mixed messages about these filters

No that's cool, I'm aware that different filters block/admit different wavelenghts for different purposes. I didn't mean to suggest the above 3 filters were doing the same job. I'll probably end up getting both LPR and UHC, maybe at the same time, maybe not. Might scour the 2nd hand market for a bit. Bintel only seem to have Astronomik or their own brand.

koputai (Jason) · #19 01-04-2008, 04:55 PM

I'll also qualify my previous post by letting you know that I live in Northern Sydney and have reasonably high light pollution. Also that the Orion Ultrablock really benefits from bigger apperture. It is a lot more usefull on the 12" than the 8". Only to be expected I suppose, as the extra light gathering in conjunction with the filter is increasing the signal-to-noise ratio (sorry, an electronics term, I'm an electronics dude).
Best check for prices carefully too, I paid $189 for the 1.25" Orion Ultrablock at a Northern Sydney shop, but a Glebe shop has it for $129.

Cheers,
Jason.

Jen · #20 01-04-2008, 07:06 PM

Quote:

Originally Posted by programmer

I wish! Never really thought I'd say that, and it probably won't happen in the next 20 years.. but one day I will. By they who knows how far the Melbourne skyglow will reach

yeah i never thought i would leave the city life either i originally come from Cranbourne. Ive been in the country for 10 years now and im never going back to the city hehehee